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Title: Effects of plasma and vacuum-ultraviolet exposure on the mechanical properties of low-k porous organosilicate glass

The effects of plasma exposure and vacuum-ultraviolet (VUV) irradiation on the mechanical properties of low-k porous organosilicate glass (SiCOH) dielectric films were investigated. Nanoindentation measurements were made on SiCOH films before and after exposure to an electron-cyclotron-resonance plasma or a monochromatic synchrotron VUV beam, to determine the changes of film hardness, elastic modulus, and crack threshold due to these exposures. This permits the effects of ion bombardment and photon bombardment to be analyzed separately. The role of energetic ions was examined with a variety of inert plasma-exposure conditions. The role of VUV photons was analyzed as a function of synchrotron photon energy. It was found that both energetic ions and VUV photons with energies larger than the bond energy of the Si-O bond cause a significant increase in film hardness along with a smaller increase in elastic modulus and crack threshold. Differential Fourier transform infrared spectra and x-ray photoemission spectroscopy results show that the energetic ions affect the SiCOH properties mainly through physical bombardment, during which the ions transfer their momentum to the Si-O-Si backbone and transform them into more energetically stable Si-O-Si network structures. This results in the Si-O-Si network structures becoming densified. VUV photons assist reaction that increasemore » the number of bridging O{sub 3}≡Si-O-Si≡O{sub 3} bonds and deplete nonbridging O{sub 3}≡Si-O and C-Si≡O{sub 3} bonds. This increased degree of cross linking in porous organosilicate dielectrics can substantially enhance their hardness and elastic modulus while showing no significant film shrinkage or densification.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [4]
  1. Plasma Processing and Technology Laboratory and Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)
  2. Performance Enhanced Biopolymers, USDA Forest Service Forest Products Laboratory, Madison, Wisconsin 53726 (United States)
  3. Applied Materials, Sunnyvale, California 94085 (United States)
  4. Stanford University, Stanford, California 94305 (United States)
Publication Date:
OSTI Identifier:
22308545
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BINDING ENERGY; CROSS-LINKING; DIELECTRIC MATERIALS; ELECTRON CYCLOTRON-RESONANCE; FAR ULTRAVIOLET RADIATION; FILMS; FOURIER TRANSFORMATION; GLASS; HARDNESS; INFRARED SPECTRA; MONOCHROMATIC RADIATION; PHOTOEMISSION; PHOTONS; PLASMA; POROUS MATERIALS; SILICATES; SPECTROSCOPY; X RADIATION